This invention relates to a new gastrostomy feeding tube or catheter and method of insertion. Gastrostomy feedings have been utilized since the late 1800s as a means of providing enteral nutrition to a patient who could not chew or swallow but otherwise had a functional gastro-intestinal system. The gastrostomy catheter allows the delivery of nutrients directly into the stomach of the patient.
Traditionally, these tubes were surgically inserted into the stomach. This required the skill of a surgeon, the use of a sterile operating theater and the presence of supporting staff, i.e., anesthesiologist, nursing team, etc., resulting in substantial cost for the patient. Additionally, the use of general anesthesia provided substantial risk to the compromised patient. Recently, the percutaneous endoscopic gastrostomy (PEG) was developed. This procedure could be performed outside the operating room, under local anesthetic and by a gastroenterologist, thereby eliminating much of the cost and risk of general anesthesia.
The PEG procedure can be divided into two types of procedures, the "push" (or "stick") procedure and the "pull" procedure. This invention relates to the development of a new gastrostomy catheter designed as a new type of "push" procedure.
In a conventional "pull" procedure, an endoscope is inserted through the esophagus of the patient, and the stomach is then inflated. Using the endoscope to locate an appropriate site in the stomach wall, a cannula or needle is then inserted through the stomach wall, and a string is inserted through the needle. The needle may then be removed. The string is grasped by means of a snare passing through the endoscope, and the endoscope and snare are pulled up through the esophagus, such that one end of the string comes out through the mouth, leaving the other end protruding through the opening made by the needle. A gastrostomy catheter is then tied to the end of the string which protrudes from the mouth, conventionally by means of another string attached at one end of the gastrostomy catheter.
The catheter is then pulled down into the stomach, by pulling on the end of the string which protrudes through the opening in the stomach, and is pulled through the opening as well, usually being provided with a tapered dilator at the leading end to assist in passing through the stomach wall. The catheter is held in place by a retention means against the interior of the abdominal wall. Another retention means is placed on the exterior, so as to hold the catheter in place against the stomach. The endoscope is reinserted to ensure proper placement of the catheter.
The pull procedure has several disadvantages, one of which is the fact that, for both emplacement and removal, an endoscope must be inserted into the patient's esophagus, requiring anesthesia and causing discomfort to the patient. Also, the catheter itself must pass through the patient's esophagus, once for emplacement and once for removal. This becomes even more problematic when secondary or replacement catheters are put in place, since each time the catheter is changed, the "pull" procedure must again be followed, with increased likelihood of trauma, infections, and other complications.
The pull procedure is particularly difficult to carry out when a patient has an obstruction in the esophagus, which is a problem compounded by the fact that it is just such people who are likely to need the procedure. Another disadvantage arises from the fact that infectious or cancerous matter may be drawn from a diseased area in, for example, the throat, down into the stomach, with the possibility of spreading the disease further, especially to the area around the freshly formed opening in the stomach.
Accordingly, a need has arisen for a gastrostomy catheter and method for emplacement which does not require access to the stomach via the esophagus.
Percutaneous gastrostomy techniques are described in detail in articles by R. Miller, et al., "The Russell percutaneous endoscopic gastrostomy: key technical steps," Gastrointestinal Endoscopy 1988: 34; 339-342, and T. Russell, et al., "Percutaneous Gastrostomy--A New Simplified and Cost-Effective Technique," American Journal of Surgery 1984:148; 132-137, which are incorporated herein by reference.
In the technique set forth by Russell, sometimes referred to as the "push" technique, a needle is first inserted into the stomach (at a site located by endoscopy, as with the pull procedure), and then a guide wire is inserted through a lumen in the needle. A small incision is then made in the fascia next to the guide wire, after which an interiorly lubricated sheath having a splittable seam is guided, along with a tapered dilator, over the guide wire and into the stomach. Once the sheath is in place, the dilator and guide wire are removed, and a balloon catheter is inserted through the lubricated central lumen of the sheath. A distal balloon of the catheter is then inflated, and the sheath is peeled or split away along its seam or seams, thus leaving the catheter emplaced in the stomach. Sutures are provided to maintain tension of the balloon against the peritoneum.
A disadvantage of the Russell procedure is that the splittable sheath is necessarily larger in diameter than the catheter which is inserted through it for emplacement within the stomach. Therefore, the opening into the stomach is made overly large, making sealing difficult and increasing the likelihood of infection. The sheath may not be made too narrow, or the physician will not be able to insert the catheter through it, and thus there is a trade-off between insertability of the catheter and the quality of the seal once the catheter is in place.
Another disadvantage of the Russell procedure is that the balloon is necessarily soft and flexible, because it must be capable of being inflated and deflated, and of being passed through the small opening into the stomach in its deflated state. Therefore, the balloon does not provide a very firm anchor for the catheter; and this is a disadvantage to all techniques relying upon balloons as anchors.
Another disadvantage of the Russell technique is that it requires the use of the splittable sheath, which increases the expense of the emplacement of the catheter.
After a gastrostomy catheter is in place, it is desirable to replace it after a time with a secondary, or replacement catheter. Such catheters are available, and a typical replacement catheter uses a flexible, enlarged tip attached at the distal end of the catheter. To insert this into the patient, a rigid rod is inserted through a lumen of the catheter into the enlarged tip, and is pressed against the inside of the tip, thus stretching it out and decreasing its diameter. In this configuration, the tip is then inserted through the opening into the stomach, and the rod is removed, allowing the tip once again to enlarge, thus providing an anchor against removal of the catheter.
This type of catheter does not provide a very reliable anchor, however, because the flexible tip may be stretched into a reduced-diameter configuration simply by a pull on the portion of the catheter which is exterior to the opening. Thus, there is always the concern that an accidental force on the catheter will result in its removal, perhaps with consequent damage to the area surrounding the opening and bleeding of the patient.
Another disadvantage of this design is that there is a direct trade-off between the expanded and reduced diameters, respectively, of the flexible tip. A larger expanded diameter leads to a more reliable anchor, and is especially necessary in a flexible-tip design. However, a larger expanded diameter requires a greater amount of material in the tip, and thus when the rod is used to stretch the tip out longitudinally, in order to reduce its diameter for insertion, this greater amount of material limits the minimum diameter, such that the tip, even when in its reduced state, may have a diameter appreciably larger than the diameter of the catheter. This leads to undesirable enlargement of the opening into the patient, resulting in less reliable sealing around the catheter once it is in place, and in greater likelihood of infection at the insertion site.
Replacement catheters often have a shorter length than primary catheters, and thus there is the problem of possible fluid leakage from the stomach through the catheter. This is not so much a problem with a longer catheter, because back-pressure is developed by the fluid. Thus, with a shorter catheter, it is helpful to provide a valve somewhere along the catheter.
One such valve is a check valve comprising a flap positioned adjacent the enlarged tip, designed to prevent backflow of fluids up the catheter, but to allow flow of fluids into the stomach. A problem with this design is that the flap may get caught in the portion of the catheter directly proximal its attachment point, thus maintaining the valve in permanently open state and defeating the check valve. Another problem with this design is that compression on the area around the valve, such as due to stress on the stomach, may force the flap open, allowing fluids to back up out of the catheter. A further problem is that, in order to decompress the patient's stomach, the valve must be opened by a rigid tool inserted into the patient's stomach.
Another type of valve used with replacement catheters is screwed to the proximal end of the catheter. This has the disadvantage of being bulky and relatively expensive, and of requiring at least a two-part system.